Hoist system having triangular tension members

(19)

(11)

EP 0 849 214 A3

(12)	EUROPEAN PATENT APPLICATION

(88)	Date of publication A3:
	01.07.1998 Bulletin 1998/27

(43)	Date of publication A2:
	24.06.1998 Bulletin 1998/26

(21)	Application number: 97401264.3

(22)	Date of filing: 05.06.1997

(51)	International Patent Classification (IPC)⁶: B66F 7/02, B66C 11/04

(84)	Designated Contracting States:
	AT BE CH DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE

(30)

Priority:

20.12.1996 US 770516

(71)	Applicant: Pri Automation, Inc.
	Billerica, MA 01821-3986 (US)

(72)	Inventors:
	Weiss, Mitchell Acton, Massachusetts 01727 (US) Friedman, Gerald M. New Ipswich, New Hampshire 03071 (US)

(74)	Representative: Joly, Jean-Jacques et al
	Cabinet Beau de Loménie 158, rue de l'Université 75340 Paris Cédex 07 75340 Paris Cédex 07 (FR)

(54)	Hoist system having triangular tension members

(57) The hoist system has triangular suspension bands that minimize sway and twisting during the lifting of a payload. The system includes three depending retractable and extensible triangular tension members (16) which provide three sets of opposed horizontal tensile forces aligned along three non-parallel lines. Each tension member comprises a flexible triangular band attached along one side to one of three rotatable spools (12) arranged at 60° to each other. The bands are attached near their vertices to a payload gripper assembly (24) which is raised or lowered as the bands are wound or unwound from the spools. The three triangular bands provide six horizontal force components which provide good lateral stability and torsional rigidity, thereby minimizing sway and twisting of the payload. The bands also provide good payload lifting strength.

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